Principal Platform Engineer (PKI)

As a Principal Platform Engineer, you will lead the design, integration and secure delivery of platforms that underpin critical defence and public sector services. You will act as a technical authority within a platform domain, guiding projects across on‑premise, hybrid and cloud environments. You’ll translate complex customer needs into robust architecture and secure-by-design designs while owning technical delivery and mentoring the next generation of engineers. This role blends hands‑on engineering with technical leadership in a collaborative, cross‑functional setting. You’ll contribute to strategic technology decisions and engage stakeholders to justify secure, scalable solutions.

• Time to Recharge: up to 12 flexi-days per year
• Employer pension contribution up to 15%
• Mental health support and financial advice
• Access to 4,000+ online courses (Coursera/LinkedIn Learning)
• Flexible benefits (private healthcare, lifestyle discounts, gym memberships)
• Hybrid working: onsite and remote options

• Act as the technical authority on a platform domain (e.g., virtualization) for projects and programmes
• Lead design and implementation of secure platforms across on-prem, hybrid and cloud environments
• Capture, analyse and interpret complex customer requirements to drive system design and architecture
• Develop high- and low-level designs aligned with secure-by-design principles
• Own the technical delivery within work packages, including planning, estimation and progress reporting
• Mentor, coach and develop junior and senior engineers to raise technical capability
• Contribute to technology strategies, feasibility studies and innovation projects
• Engage with internal and external stakeholders, presenting technical solutions and justifying design decisions

• Extensive technical expertise across multiple platform domains with a track record of delivering secure solutions
• Ability to balance hands-on engineering with technical leadership and mentorship
• Strong problem-solving mindset with capability to innovate for complex challenges
• Core areas (must have): Windows and Linux operating systems; Virtualisation platforms (VMware, Hyper-V); PKI design and implementation; Certificate lifecycle management; PKI integration with enterprise platforms (Active Directory, applications, devices); Cryptographic principles and secure communications; Networking concepts (TCP/IP, DNS, DHCP, firewalls); Automation and scripting (PowerShell, Bash, Python, Ansible, Terraform); Knowledge of cyber security controls and accreditation requirements; Experience across the systems engineering lifecycle; Design and assurance of trust models and certificate usage; Delivery within highly controlled/secure environments (defence, air-gapped)

• Mentoring and coaching
• Stakeholder engagement and communication
• Problem-solving mindset and collaboration
• Windows and Linux administration
• VMware and Hyper-V virtualization
• PKI design and certificate management